* {
    margin: 0;
    padding: 0;
}

.header {
    width: 100%;
    height: 40px;
    background-color: grey;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-left {
    margin-left: 20px;
    /* border: 1px solid red; */
}

.header-right {
    margin-right: 20px;
    /* border: 1px solid red; */
}

.header-left-item1,
.header-right-item2 {
    font-weight: 700;
    color: #fff;
    font-size: 24px;
}

.header-left-item2,
.header-right-item1 {
    font-size: 24px;
    color: yellow;
}

.hidden {
    width: 30px;
    height: 30px;
    display: none;
}


/* 第一部分样式 */

.first {
    background-color: grey;
    height: 650px;
}


/* flex-direction定主轴方向
justify-content: center主轴方向居中
align-items: center垂直方向居中
*/

.first-text {
    height: 650px;
    display: flex;
    color: seashell;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    /* border: 1px solid red; */
}

.first-text-one {
    font-size: 14px;
}

.first-text-two {
    font-size: 45px;
}


/* 第二部分样式 */

.second {
    /* height: 650px; */
    background-color: silver;
}

.second-top {
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: sans-serif;
    font-size: 35px;
    font-weight: 600px;
    color: rgb(103, 105, 108);
}

.second-center {
    text-align: center;
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
    font-weight: 300;
    color: rgb(103, 105, 108);
}

.second-bottom-one-top,
.second-bottom-two-top,
.second-bottom-three-top,
.second-bottom-four-top {
    font-size: 20px;
    font-weight: 300;
    color: rgb(103, 105, 108);
}

.second-bottom-one-bottom,
.second-bottom-two-bottom,
.second-bottom-three-bottom,
.second-bottom-four-bottom {
    margin: 20px 0;
}


/* 对首字母进行修饰 */

.second-bottom-one-top::first-letter {
    color: grey;
    font-size: 80px;
}


/* 第三部分修饰 */

.third-top {
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.third-center {
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.a {
    width: 100%;
    margin: 20px auto;
    transition: all 1s;
}

.a:hover {
    transform: rotateY(180deg);
}


/* 第四部分 */

.four-top {
    height: 80px;
    font-size: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.four-mid {
    height: 80px;
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.b {
    width: 100%;
    margin: 20px auto;
}

.picture {
    overflow: hidden;
}

.b:hover {
    animation: picture 2s infinite alternate;
}

@keyframes picture {
    form {}
    to {
        transform: scale(3);
    }
}


/* 第五 */

.five {
    background-color: grey;
}

.five-top {
    height: 80px;
    font-size: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.five-center {
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center
}

.bottom-top-right {
    display: flex;
}

.bottom-zuobian {
    display: flex;
    justify-content: space-between;
}

.bottom-center {
    display: flex;
}

.bottom-center-left {
    display: flex;
    justify-content: space-between;
}

.bottom-bottom {
    display: flex;
}

.bottom-bottom-left {
    display: flex;
    justify-content: space-between;
}

.bottom-center {
    margin-top: 20px;
}

.bottom-bottom {
    margin-top: 20px;
}

.bottom-bottom-right input {
    height: 100px;
}